Mounted it on my Kel-Tec Sub-2000 about 3 months ago. Took it out of the safe this morning and the battery is dead. I will install a new battery and see if it lasts longer this time. If not, it might be headed back to PA.

Put a name brand, quality battery in it and you should be good to go. The cheap battery that comes with it has been known to fail early, from reports on other forums.

Fortunately, the batteries are cheap. This is my "non-handgun" gun that rides in a spare computer bag and goes where no handgun is allowed to go (30.06 locations). So, the good news is that I do have the ability to check the battery before each use. I will just keep a few spares in the same computer bag, and get in the habit of double-checking it before heading out.

Now if this had been the optic on my bed-side long gun (currently a KSG), that would have been much more concerning. When something goes bump in the night I don't exactly have time to change batteries in my red dot.